Limited scope for plasticity to increase upper thermal limits

Research output: Contribution to journalArticleResearchpeer-review

Abstract

1. Increases in average temperature and the frequency of extreme temperature events are likely to pose a major risk to species already close to their upper physiological thermal limits. The extent to which thermal phenotypic plasticity can buffer these changes and whether plasticity is constrained by basal tolerance levels remains unknown. 

2. We examined the effect of developmental temperature under both constant and fluctuating thermal regimes (developmental acclimation), as well as short-term heat hardening, on upper thermal limits (CTmax) in a tropical and temperate population of Drosophila melanogaster

3. We found evidence for thermal plasticity in response to both developmental acclimation and hardening treatments; CTmax increased at warmer developmental temperatures and with a prior heat hardening treatment. However, hardening and acclimation responses were small, improving CTmax by a maximum of 1·01 °C. These results imply that overheating risk will only be minimally reduced by plasticity. 

4. We observed significant associations between developmental temperature and both basal CTmax and hardening capacity (a measure of the extent of the plastic response). Basal CTmax increased, while hardening capacity decreased, with increasing developmental acclimation temperature. This indicates that increases in basal heat resistance at warmer temperatures may come at the cost of a reduced capacity to harden. 

5. While plasticity in CTmax is evident in both populations of D. melanogaster we studied, plastic increases in upper thermal limits, particularly at warmer temperatures, may not be sufficient to keep pace with temperature increases predicted under climate change. A lay summary is available for this article.

Original languageEnglish
Pages (from-to)1947-1956
Number of pages10
JournalFunctional Ecology
Volume30
Issue number12
DOIs
Publication statusPublished - 1 Dec 2016

Keywords

  • acclimation
  • climate change
  • CTmax
  • hardening
  • heat
  • reaction norm
  • thermal tolerance

Cite this

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title = "Limited scope for plasticity to increase upper thermal limits",
abstract = "1. Increases in average temperature and the frequency of extreme temperature events are likely to pose a major risk to species already close to their upper physiological thermal limits. The extent to which thermal phenotypic plasticity can buffer these changes and whether plasticity is constrained by basal tolerance levels remains unknown. 2. We examined the effect of developmental temperature under both constant and fluctuating thermal regimes (developmental acclimation), as well as short-term heat hardening, on upper thermal limits (CTmax) in a tropical and temperate population of Drosophila melanogaster. 3. We found evidence for thermal plasticity in response to both developmental acclimation and hardening treatments; CTmax increased at warmer developmental temperatures and with a prior heat hardening treatment. However, hardening and acclimation responses were small, improving CTmax by a maximum of 1·01 °C. These results imply that overheating risk will only be minimally reduced by plasticity. 4. We observed significant associations between developmental temperature and both basal CTmax and hardening capacity (a measure of the extent of the plastic response). Basal CTmax increased, while hardening capacity decreased, with increasing developmental acclimation temperature. This indicates that increases in basal heat resistance at warmer temperatures may come at the cost of a reduced capacity to harden. 5. While plasticity in CTmax is evident in both populations of D. melanogaster we studied, plastic increases in upper thermal limits, particularly at warmer temperatures, may not be sufficient to keep pace with temperature increases predicted under climate change. A lay summary is available for this article.",
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Limited scope for plasticity to increase upper thermal limits. / van Heerwaarden, Belinda; Kellermann, Vanessa; Sgro, Carla.

In: Functional Ecology, Vol. 30, No. 12, 01.12.2016, p. 1947-1956.

Research output: Contribution to journalArticleResearchpeer-review

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